Heretofore, electrostatically operated print heads and electro-luminescent displays have required the use of external control circuitry to supply a high-voltage ramp waveform and to employ a large holding capacitor and 7-bit data words to select the particular value reached by the ramp waveform to drive a particular pixel to the desired level of shading intensity. The range of gray-level shading intensity typically requires 16 levels of voltage between 0 volts and 300 volts to be provided by the external ramp voltage generator. The 7-bit data word was needed to achieve the desired accuracy in designating the gray level voltage. To reduce the cost of such displays and provide for high resolution, it would be desirable to integrate the driving and control circuitry together with the circuitry of the print head or display unit itself, provided this can be done without degrading the resolution or granularity of the display. However, the circuitry required to generate the ramp function voltage and process the 7-bit data word, as well as the large capacitor required to store the ramp function voltage, requires an inordinate amount of silicon and heretofore it has not been possible to achieve the desired degree of component concentration.